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Fly ash (FA) is a complex and abundant solid waste created by humans, and has caused environmental issues, for which flotation is an effective technique employed before its comprehensive utilization. However, the complex and hydrophilic characteristics of FA particles cannot naturally fulfill the selective separation by common flotation. Therefore, this study aims to provide an insight into fluid intensification effects on flotation to achieve the enhancement of FA surface property and decarburization. The relevant effects and mechanisms are investigated, based on the measurements of zeta potential, infrared spectroscopy, contact/wrap angle, induction time, size distribution and scanning electron microscopy–energy dispersive spectrometry. Experimental results manifested that the maximum unburned carbon recovery (73.25%) and flotation rate (0.2037 s–1) were achieved with preconditioning energy inputs of 14.23 and 6.57 W·kg–1 respectively. With increasing preconditioning energy inputs, fluid intensification effects could promote the inter-particle collision/attrition, detachment of hydrophilic existence and collector adsorption on particles. Correspondingly, absorbance of some hydrophobic and hydrophilic functional groups was strengthened and weakened respectively, which accounted for the improved interfacial properties, reflected as the increased contact and wrap angles, together with declined induction time. Overall, this article revealed the positive influences of fluid intensification based preconditioning process on rendering particle surface hydrophobic and improving separation performance.

Perovskite solar cells (PSCs) have become a promising photovoltaic (PV) technology. Meanwhile, developing an electron transport layer (ETL) has been an effective way to promote the power conversion efficiency (PCE) of PSCs. Here, a 4-morpholine ethane sulfonic acid sodium salt (MES Na+) doped SnO2 ETL is utilized in planar heterojunction PSCs. The results show that the MES Na+ doped ETL can improve the crystallinity, and absorbance of perovskite films, and passivate interface defects between the perovskite film and SnO2 ETL. The doping effect accounts for the enhancement of conductivity and the decreasing work function of SnO2. When 10 mg mL-1 MES Na+ was added to the SnO2 precursor solution, the device showed the best performance Jsc, Voc, and FF of the PSCs values, which were 23.88 mA cm-2, 1.12 V and 78.69%, respectively, and the PCE was increased from 17.43% to 21.05%. This doping ETL strategy provides an avenue for defect passivation to further increase the efficiency of perovskite solar cells.

SrFeO3-δ perovskite material is considered as a potential substitute for Ni-based fuel electrodes, while the problem of Sr segregation limits the development of material. Herein, different high-valence elements Ti4+, Nb5+and Mo6+ are gradient doped into La0.5Sr0.5FeO3-δ (LSF) to solve Sr segregation and study the influence mechanism for high valence elements. After the LSF is doped by high-valence elements, the reduction stability and CO2 tolerance are found to be obviously improved in a CO2:CO = 1:1 atm. Under the premise of stability, lower-valence element doping requires less Fe4+ reduction and lattice oxygen to match the charge, therefore, La0.5Sr0.5Fe0.9Ti0.1O3-δ (LSFTi5591) possesses more oxygen vacancies than La0.5Sr0.5Fe0.9Nb0.1O3-δ (LSFNb5591) and La0.5Sr0.5Fe0.9Mo0.1O3-δ(LSFMo5591). Since Ti ions possess a weaker binding force with O ions, LSFTi5591 more easily loses lattice oxygen and generates oxygen vacancies under high-temperature and reduction conditions, which results in stronger CO2 adsorption. Using LSCF-GDC as the oxygen electrode of electrolytic cells, the LSFTi5591 cell (1.35 A cm−2) exhibits higher electrochemical performance than LSFNb5591 (1.18 A cm−2) and LSFMo5591 (1.04 A cm−2) cells due to stronger CO2 adsorption and dissociation in the medium-frequency resistance range.

La-doped Sr2-xLaxFe1.5Mo0.5O6-δ perovskite oxides are synthesized and used as a symmetric electrode to evaluate the effect of La on the crystal structure, conductivity, and catalytic activity for O2 reduction and H2 oxidation reaction. The electronic doping effect dominates the oversize effect in Sr2-xLaxFe1.5Mo0.5O6-δ oxide, resulting in unit cell volume expansion and decreased conductivity in air. In addition, the introduction of La increases the chemical structural stability of Sr2Fe1.5Mo0.5O6-δ in reducing condition due to the higher La–O bond compared with Sr–O bond, leading to high catalytic activity for the H2 oxidation reaction. At 800 °C, the Rp values of Sr1.9La0.1Fe1.5Mo0.5O6-δ symmetric cell in air and wet H2 are as low as 0.075 and 0.21 Ω cm2, respectively. Moreover, the peak power densities of 769, 561, 439, and 653 mW cm−2 at 850 °C are obtained when wet H2, CO, CH4, and C3H8 are used as fuels on Sr1.9La0.1Fe1.5Mo0.5O6-δ/LSGM/Sr1.9La0.1Fe1.5Mo0.5O6-δ cell. The symmetric cell also shows excellent stability (>100 h) in wet H2/air, implying Sr1.9La0.1Fe1.5Mo0.5O6-δ oxide is a promising symmetric electrode material.

In this paper, the integrated characteristics of a fluidized bed combining a distributed entrained flow bed in a new reactor, and the oxygen enriched gasification performance of biomass in the integrated reactor were studied numerically on the basis of experiments. A 3D numerical model was established by FLUENT and Eulerian-Lagrangian method was selected to solve the model. Simulation results show the integrated characteristics, where the lower-stage of the reactor performs the characteristics of distributed entrained flow, and the upper-stage shows fluidized bed characteristics by fluid upward returning. In addition, the influencing factors of oxygen-carbon mass ratio (O/C) and oxygen concentration of gasification agent, were studied based on experiment. The results show that as the O/C increases, the concentrations of H2 and CO2 in the syngas gradually decreases but the CO concentration remains stable. The effect of O2 concentration on syngas composition is related to its O/C. The concentrations of CO and CO2 rise as the O2 concentration increases. However, when the O/C is between 0.35 and 0.55, as the oxygen concentration increases, the H2 concentration shows a trend of firstly increase and then decrease. All the numerical and experimental results are in good agreement.

In this study, the carbothermic reduction and volatilization were applied to recover valuable metals from lead slag. The removal and volatilization mechanisms, especially the migration and distribution behavior of heavy metals, were investigated. The results showed that the removal ratio of Sn was lower than those of Pb and Zn. Increasing the temperature was beneficial to the removal of Zn, but unfavorable for the removal of Sn and Pb. SEM/EDS analysis of the reduced pellets and the flue dust showed that ZnFe2O4 and ZnS in the raw slag were reduced to Zn for volatilization and then reoxidized and formed ZnO(s) in the flue. At lower temperatures, SnO2 and FeOx·PbO·SiO2 in the raw slag was reduced to the volatile SnO and PbO. However, SnO and PbO were further reduced to nonvolatile metallic Sn and Pb at higher temperatures. Fe-Sn and Fe-Pb alloys easily formed when metallic Sn and Pb coexisted with metallic Fe, leading to lower removal ratios. For the metallization of Fe, the iron grains grew up gradually and easily formed joined crystals at higher temperatures, which inhibited the volatilization of Sn and Pb.

A three-dimensional (3-D) model for multispecies vacuum arc considering ionization and recombination process has been built in this article. With the model, the arc behaviors and species characteristics subjected to actual spatial magnetic fields of cup-shaped axial magnetic field (AMF) contact and transverse magnetic field-axial magnetic field (TMF-AMF) contact are investigated and compared. Furthermore, the validity of the model is verified by comparing with the experiments. Simulation results show that contact structures affect the species distributions of the arc by changing magnetic field and current density distributions. More triple charged ions are generated through ionization under higher electron temperature so that the triple charged ions gather where current constricts. The heat flux density is large in the current contraction region, where the contribution from triple charged ions is large as well. Spatial magnetic field distribution affects the Lorentz force acting on ion components. The force distribution is relatively uniform and the species are subject to inward force on the arc edge under cup-shaped AMF contact. For TMF-AMF contact, the double charged ions are subject to the force pointing to the TMF contact arms, whereas the triple charged ions are subject to the force pointing to the arc center. In addition, the consideration of arc species can improve the accuracy of the simulation results of the heat flux distribution, leading to a good agreement of the erosion condition between experiments and simulation.

The investigation of flow field can provide strong theoretical support for improving the flotation performance of fine particles in a cyclonic flotation column. In this study, particle image velocimetry (PIV) is combined with endoscopic measurement and phase discrimination technique to measure the cross section and axial section of gas–liquid two-phase flow field in a lab-scale cyclonic flotation column. The axial, radial, and tangential velocity of both gas and liquid phases are obtained. Based on the PIV experimental data, computational fluid dynamics (CFD)-based numerical models are validated. The results show the good prediction ability of Eulerian–Eulerian multiphase model, Reynolds stress model (RSM), and Tomiyama drag model. Then the simulated results with validated models are displayed to indicate the flow characteristics of the flotation column. The gas concentration is observed to be higher in the center and low on the sides. The gas phase always moves upward, while the liquid phase moves upward at the axis, downward between the axis and the wall, and upward again near the wall. Overall, this study provides an innovative approach for PIV measurement of complex multiphase flow field, and a useful reference for appropriate numerical models selection.

A novel technology was proposed to fabricate non-stoichiometric titanium dioxide (TiO2−x) compacts in one-step thermal process by in-situ reduction of rutile TiO2 with carbon powder via spark plasma sintering (SPS). The rutile TiO2 powder was reduced with three different carbon powders for comparison, and the effect of the sintering conditions on the fabricated compacts was investigated. It is found that the in-situ reduction of rutile TiO2 with charcoal powder was easily achieved at a low pressure and high temperature (above 1473 K). Besides, the design of dynamic sintering pressure during SPS was proposed, and the results suggest that the dynamic sintering pressure contributes to the reduction of TiO2 and the fabrication of the compacts with high-density. In addition, density methods, X-ray diffraction, scanning electronic microscopy and laser micro-Raman spectrometer were performed to analyze the sintering sates, microstructures, crystal structures and phase distributions. The results show that a stable sintering environment without an increase in the pressure caused by reaction gas is a crucial role for the reduction of TiO2 and the TiO2−x fabrication, even the formation of Magneli phases TinO2n−1. Finer charcoal powder is more conducive to fabricating the compact with a single Magneli phase Ti6O11. It is expected to achieve a new breakthrough in fabrication method of the non-stoichiometric TiO2 by a safe and economically viable method.

As a special phenomenon under transverse magnetic field (TMF) contacts, vacuum arc rotation deserves more attention. In this article, rotation characteristics of three typical TMF contacts, i.e., swastika-type, cup-shaped, and double-TMF contacts, are systematically studied. According to arc images, recorded by a high-speed camera, physical terms related to arc rotation such as rotation duration and rotation speed are clearly defined. The magnetic field and Lorentz force are calculated and the force balance of the moving arc is analyzed. On this basis, the effects of arc ignition mode, peak current, and contact type on arc rotation are investigated. Arc voltage noise as well as arc splashing outside caused by rotation is also discussed. The results show that the duration from ignition to rotation in two-point arc ignition (TPAI) mode is usually the shortest because of the rapidest constructed column formation. As the peak current increases, arc rotation becomes easier. Due to stronger TMF, the arc under double-TMF contacts has the longest rotation duration and the highest rotation speed.

In comparison with the common-used electron donor (D)-electron acceptor (A) type symmetric polymers with regular structures, their asymmetric counterparts have received much less attention and seldom been applied in polymer solar cells. Since the precise modulation of π bridge can significantly influence the photoelectric properties of D-A type polymers, π bridges of tailorable thiophenes are introduced into benzodithiophene (BDT)-benzodithiophene-4,8-dione (BDD) copolymers in both symmetric and asymmetric patterns. Together with the halogen substituent of fluorine or chlorine on BDT, four polymer donors are designed and synthesized. As expected, PTB2T-F and PTB2T-Cl with the asymmetric π bridges of thiophene and hexyl-bithiophene exhibit better planarity, stronger intermolecular interaction and higher hole mobility than P2TB2T-F and P2TB2T-Cl with the symmetric π bridges of hexyl-bithiophene. The more suitable phase separation and optimized nanomorphology is determined by the reasonable miscibility between asymmetric polymer and acceptor, which is evaluated by Flory-Huggins interaction, contributing to the extremely higher performance than that of symmetric counterpart. Moreover, paired with IT-4F as the acceptor, PTB2T-F affords better device performances than the reference BDT-BDD polymer PM6 with the symmetry π bridge of thiophene. These results demonstrate that the precise modulation of asymmetric π bridges is a promising strategy to construct high-efficiency D-A type polymer donors.

The desulfurization mechanism is of great significance to quality improvement in metallurgical process. In this work, the structural features, chemical and dynamical properties of the liquid FeO·SiO2 were calculated under 2000 K through ab initio molecular dynamics simulations. Further calculation of desulfurization was conducted based on the structural evolution information. The results showed that the liquid FeO·SiO2 is primarily constituted by Si–O and Fe–O bonds, with the former being strong covalent bonds, while the latter showing the feature of ionic bonding. Bader charges analysis indicated that Fe and O have a wide range of charge states, while that of Si is relatively concentrated. It is found that the sulfur atom that is incorporated into the liquid FeO·SiO2 tends to form a stable bonding structure with three iron atoms, and the Si–S bond seems to be unstable thus, unable to exist in the S-doped FeO·SiO2 silicate.

Solid oxide cells (SOCs) can switch between fuel cell and electrolysis cell modes, which alleviate environmental and energy problems. In this study, the La0.3Sr0.7Fe0.9Ti0.1O3-δ (LSFTi 91) perovskite is innovatively used as a symmetric electrode for solid oxide electrolysis cells (SOECs) and solid oxide fuel cells (SOFCs). LSFTi 91 exhibits a pure perovskite phase in both oxidizing and reducing atmospheres, and the maximum conductivity in air and 5% H2/Ar is 150 and 1.1 S cm-1, respectively, which meets the requirement of the symmetric electrode. The polarization resistance (Rp) at 1.5 V is as low as 0.09 Ω cm2 in the SOEC mode due to the excellent CO2 adsorption capacity. The current density can reach 1.9 A cm-2 at 1.5 V and 800 °C, which is the highest electrolytic performance in the reported single-phase electrodes. LSFTi 91 also exhibits eminent oxygen reduction reaction and hydrogen oxidation reaction (ORR and HOR) activities, with Rp of 0.022 and 0.15 Ω cm2 in air and wet H2, respectively. The peak power density of SOFC could reach 847 mW cm-2 at 800 °C. In addition, good reversibility is confirmed in the cyclic operation of SOFC and SOEC.

A comparative study on CaO–MgO–Al2O3–SiO2 slag and CaO–MgO–Al2O3–SiO2–Cr2O3 slag was conducted to investigate the distribution of the elements at the gas-slag interface. The effect of redox states of chromium on the distribution of sulfur and oxygen at the interface was revealed by gas-slag equilibrium method using X-ray photoelectron spectroscopy at 1873K. From the analysis of the S2p core-level spectra, the negative divalent sulfur(S2−) was detected at the interface in the Cr-bearing slag, which directly proved that sulfur exists in the form of S2− in the slag for the first time. However, the S2− peak is very weak at the interface of Cr-free slag. The reason for the difference between the two slags may be due to chromium changing the interface structure. According to the O1s and Cr2p core-level spectra, non-bridged oxygen(O−) increased, while bridged oxygen(O0) decreased with the etching depth deepened. The increase of NBO/BO and Cr2+/Cr3+ elucidates that Cr3+ can modify the structure of the slag as basicity substance, but its effect is weaker than that of Cr2+. Meanwhile, due to the affinity of sulfur and chromium, the addition of chromium may also lead to the enhancement of the S2− peak at the gas-slag interface. Gradient change of elements at the interface proved the existence of the boundary layer.

In this work, a new polishing method for zirconia ceramics was firstly proposed, which combined dielec-trophoresis effect with magnetic compound fluid polishing. A key experimental device was designed and constructed, and the influence behavior of dielectrophoresis phenomenon on the polishing efficiency, surface roughness and glossiness of zirconia ceramic workpiece were investigated. Also, the effects of voltage, electrode shape and electric field parameters on the polishing results were deeply discussed. The results showed that when the magnetic field was stronger, the polishing efficiency would become higher, while the surface quality of the workpiece getting worse. And the glossiness was positively correlated with the surface roughness. Moreover, the smaller the electrode shape and the larger the electric field gradient caused the better dielectrophoresis-assisted effect. It was indicated that when the electrode shape was a circle with a diameter of 20 mm and the voltage was 1500 V, the material removal efficiency was improved by 36.4% while ensuring the surface quality of zirconia ceramics.

In this paper, the compound heat transfer of convection and radiation in an internal circulating fluidized bed for low temperature oxidation of pulverized coal was numerically simulated. The numerical prediction about the compound heat transfer characteristics and its relationship of convection and radiation was compared with the experimental measurements of low temperature radiation. The discrete ordinate model (DOM) was employed to investigate the radiation heat transfer in the low temperature oxidation internally fluidized bed, and user-defined function (UDF) was compiled by considering the effect of the particle flow emissivity on radiation heat transfer. The convection heat transfer coefficient increases with the increase of gas inlet volume flow rate and initial bed material height, however, thermal radiation coefficient was opposite. An increase of the thermal flux results in an increase of the surface temperature of the fluid and the heater surface, and the thermal transfer coefficient between bed material and heater surface is also increased. The results have the application reference to complex thermal transfer design of circulating fluidized bed systems wherein thermal radiation transfer must be considered as a significant mode.

We demonstrate a distributed feedback (DFB) semiconductor laser based on i-line lithography and surface periodic current injection technologies with a lasing wavelength of 795 nm, which corresponds to the D1 spectrum of Rb and has many applications with respect to alkali vapor lasers and atomic clocks. The maximum output power, side mode suppression ratio (SMSR), and single-longitudinal-mode tunable range of our device are 50.89 mW (at 20 °C), 34.56 dB, and 12.792 nm, respectively. The rate of change in wavelength with temperature of the laser is 0.401 nm/°C, which is equivalent to that of a Fabry-Perot (FP) laser and much better than that of a general DFB device. This device has a cavity the same as an FP laser without any etching gratings, meanwhile the lasing spectrum behaves a single longitudinal mode characteristic as a DFB laser.

This study was to investigate the effect of different drying methods on the drying kinetics, physical properties, and bioactivity of Platycodon grandiflorum (PG). Four drying methods were employed to conduct the dehydrated process, namely, hot air drying (AD), vacuum drying (VD), microwave hot airflow rolling-bed drying (MHARD), and pulse-spouted microwave vacuum drying (PSMVD). PSMVD showed the highest drying rate among four drying methods based on the result of fitting first-order reaction model. And PSMVD-dried product showed higher rehydration ratio and better mechanical properties, suggesting a better rehydration characteristic. In addition, considering the content of Platycodin D, PSMVD is a promising drying technology for the dehydration of PG.

The vanadium slag (V-slag) is generated from smelting vanadium titanomagnetite ore, which contains valuable elements, such as V, Ti, Cr, Fe, and Mn. The traditional methods were mainly focused on the extractions of V and Cr by oxidation or reduction processes. In the present work, chlorination method was adopted to keep the valence state of each element in original state. In order to speed up the diffusion of elements and reduce volatility of molten salt, microwave heating was examined in the current paper. The results indicated that it only took 30 min to chlorinate V-slag at 800 ?C, and the chlorination ratios of V, Cr, Mn, Fe, and Ti reached to 82.67%, 75.82%, 92.96%, 91.66%, and 63.14%, respectively. Compared with the results by conventional heating for 8 h, this extraction rate by microwave heating showed greater advantages. In addition, microwave heating effectively reduced volatilization of AlCl3 by shortening the reaction time. The volatilization ratio of AlCl3 in this microwave heating was 3.92% instead of 8.97% in conventional heating (1h). The mechanism of efficient chlorination can be summarized as the enhancement of ions diffusion process and enhanced chemical reaction due to local high temperature.

Solid oxide electrolysis cells (SOECs) are a new type of high-efficiency energy conversion device that can electrolyze CO2 efficiently and convert electricity into chemical energy. However, the lack of efficient and stable cathodes hinders the practical application of CO2 electrolysis in SOECs. Herein, a novel perovskite oxide La0.5Sr0.5Fe0.95Mo0.05O3−δ (LSFMo) is synthesized and used as a cathode for SOECs. The introduction of Mo significantly improves the CO2 tolerance of the material in a reducing atmosphere and solves the problem of SrCO3 generation in the La0.5Sr0.5FeO3−δ material. Mo ion doping promotes the conductivity in a reducing atmosphere and increases the oxygen deficiencies of the material, which lowers the ohmic resistance (Rs) of the material and significantly improves the CO2 adsorption and dissociation in the middle-frequency of polarization resistance (Rp). For example, Rp decreases from 0.49 to 0.24 Ω cm2 at 800 °C under 1.2 V. Further, the reduction of Rs and Rp increases the performance improvement, and the current density is increased from 1.56 to 2.13 A cm−2 at 800 °C under 2 V. Furthermore, LSFMo shows reasonable short-term stability during the 60 h stability test.

The specific heat of aqueous graphene+Al2O3 (1:1) hybrid nanofluid was measured using the cooling method. The influence of nanoparticle mass fraction and temperature on the specific heat capacity of the hybrid nanofluids was investigated, the specific heat of the hybrid nanofluid was compared with that of aqueous graphene oxide nanofluid and Al2O3 nanofluid. A fitted formula of the specific heat of the hybrid nanofluid was proposed based on the experimental data. It indicates that the specific heat reduction ratio increases with increase of nanoparticle fraction and the maximum reduction ratio is 7% at 0.15 wt.% at 20?C. The mass fraction of nanoparticle affects the specific heat of hybrid nanofluid more significantly at lower temperature. Temperature impacts the specific heat more distinctly than the nanoparticle fraction. The specific heat increases with temperature and the maximum specific heat reduction ratio of the hybrid nanofluid diminishes from 7% at 20?C to 2% at 70?C at the mass fraction of 0.05%.

Ti–6Al–4V is considered to be the most important and useful alloy in the aerospace industry and many other fields. The growing demand for high productivity in machining requires a novel technique for drilling this material efficiently. In this article, a novel grinding technique for drilling with a combination of ultrasonic-assisted grinding and plasma electrolytic oxidation is proposed. The technique was hence named ultrasonic-assisted plasma oxidation grinding (UPOG). A thin oxidized layer was formed on the surface of the workpiece in the grinding zone by plasma. This could enable a reduction of the expensive grinding wheel, which could lead to environmental friendly machining. The oxidized layer would be much softer than the original material. To reveal its fundamental performance in the drilling of Ti–6Al–4V, experiments were conducted to investigate the effect of ultrasonic vibration on grinding forces and tool wear in the presence of plasma oxidation. To investigate the material removal process for UPOG, nanoindentation and nanoscratch tests were also conducted with plasma oxidation samples.

Organo–mineral interactions have long been the focus in the fields of biomineralization and geomineralization, since such interactions not only modulate the dynamics of crystal nucleation and growth but may also change crystal phases, morphologies, and structures. The utilization of an atomic force microscopy (AFM)-based dynamic force spectroscopy (DFS) technique makes it possible to quantify the single-molecule scale organo–mineral binding free energy (ΔGb) correlated with interfacial free energy (γ) and the nucleation energy barrier (ΔG). In this highlight, we briefly review theories of force spectroscopy (FS) and DFS, indicating that single-molecule force spectroscopy (SMFS) can be distinguished with the worm-like chain (WLC) model, and linear and nonlinear DFS data can be analyzed with the Bell–Evans and Friddle–Noy–De Yoreo models to derive noncovalent binding information through the introduction of detailed procedures for DFS experiments from AFM tip modification to FS collection. Moreover, we present some application cases of DFS in unraveling the mechanisms underlying organo-modified nucleation rates, nucleus critical sizes, and phase transformations as well as facet-dependent organo–mineral interactions. The use of an AFM-based DFS technique will improve the fundamental understanding of organo–mineral interactions that affect organo-modified crystal nucleation and growth in both biomineralization and geomineralization processes.

Semiconductor optical amplifiers (SOAs) offer direct electrical injection, power consumption, integration, and anti-radiation advantages over optical fiber amplifiers. However, saturation output power and gain bandwidth have been limited in traditional structure SOAs. We demonstrate a monolithic integrated SOA with broad spectrum, high power, high gain, and small spectral linewidth expansion. The device adopts a two-stage amplified large optical cavity structure, and a lower optical field confinement factor is obtained by adjusting the thickness of the waveguide layer. The lower optical field confinement factor is conducive to improving the coupling efficiency and the maximum output power. Our device, fabricated only by standard i-line lithography with micron-scale precision, obtains excellent and stable performance. When the input power is set to 1 mW, the output power is 419 mW with a gain of 26.23 dB. When the input power is set to 25 mW at 25 °C, the output power increases to 600 mW with a gain of 13.8 dB. The corresponding gain bandwidth of 3 dB measures at least 70 nm. The spectral linewidth after the SOA is 1.15 times wider than that of the seed laser.

In this article, the model including cathode spot process and deuterium desorption process on zirconium deuterium cathode is developed. Five kinds of particle fluxes on cathode surface and three mechanisms affecting deuterium diffusion in cathode are considered. The model not only describes the deformation of cathode metal, but also describes the variation of deuterium concentration with time. On pure zirconium cathode, the mean charge state is larger but on zirconium deuterium cathode, the total ion number density is larger since there are additional deuterium ions, and simulation results show the discharge currents are very close on the two cathodes, the energy flux density on ZrD0.66 cathode is larger so cathode spot crater develops faster on ZrD0.66 cathode. Ablation rates caused by different mechanisms are calculated and the results show in cathode spot development process, mass loss caused by evaporation is ignored, most of the liquid metal will resolidify on cathode surface, and droplets are the main reason for cathode ablation. The ablation rates due to the ejection of droplets are close to experimental results. The ratios of deuterium ion from different mechanisms in this process are also calculated and it is 93.5% in simulation. Simulation results are in agreement with the other researchers’ works.

A 3D computational hydrodynamics model (CFD) of a two-stage entrained-flow biomass gasifier is developed for further engineering application of the clean utilization of renewable energy. The biomass gasification procedure in the entrained-flow gasifier is simulated with the CFD software FLUENT®15.0. The Eulerian-Lagrangian method is applied to model the two-phase chemical reaction and heat transfer flow. Based on the multi-step chemical reaction dynamics, the homogeneous and heterogeneous biomass gasification reaction are described, respectively. The realizable k-e model describes the turbulent flow of gas phase, and the motion of pulverized-biomass particles is tracked by the stochastic tracking method (STM). Using steam-air as gasification agent, different reaction mechanisms are simulated to compare with the verification value to find the optimal reaction mechanism. Then the quantitative influence of the main parameters of biomass gasification, namely, different equivalent ratios (ER), steam-to-biomass mass ratios (S/B), and the distribution ratios between the upper and lower stages (DR) are studied with the orthogonal analysis method. The results show that the proper values of ER, S/B and DR are helpful to improve gasification performances, such as maximum flame temperature, syngas compositions, active components, carbon conversion rates, etc. The optimum parameters for gasification condition are found as S/B = 0.1, ER = 0.16, DR = 30%/70%.

Tailings from the vanadium extraction process are discarded each year as waste, which contain approximately 30wt% of Fe. In our previous work, we extracted Fe and Mn from vanadium slag, and Fe and Mn existed in the form of FeCl2 and MnCl2 after chlorination by NH4Cl to achieve effective and green usage of waste containing Fe and Mn. In this work, square wave voltammetry (SWV) and cyclic voltammetry (CV) were applied to investigate the electrochemical behaviors of Fe2+ and Mn2+ in NaCl-KCl melt at 800°C. The reduction processes of Fe2+ and Mn2+ were found to involve one step. The diffusion coefficients of FeCl2 and MnCl2 in molten salt of eutectic mixtures NaCl-KCl molten salt were measured. The electrodeposition of Fe and Mn were performed using two electrodes at a constant cell voltage. The Mn/Fe mass ratio of the electrodeposited product in NaCl-KCl-2.13wt%FeCl2-1.07wt%MnCl2 was 0.0625 at 2.3 V. After the electrolysis of NaCl-KCl-2.13wt%FeCl2-1.07wt%MnCl2 melted at 2.3 V, the electrolysis was again started under 3.0 V and the Mn/Fe mass ratio of the electrodeposited product was 36.4. This process provides a novel method to effectively separate Fe and Mn from simulated chlorinated vanadium slag.

Hole-transporting layer (HTL) plays a key role in most high-efficiency perovskite solar cells (PVSCs). Especially in the n-i-p conventional PVSCs, HTL promotes device performances through multiple ...

To develop a simple and effective method for fabricating a type of transparent p-type zinc oxide (ZnO) thin films, potassium-doped ZnO (K-ZnO) thin films were designed and prepared via molten-salt treatment (MST) in KNO3 for n-type ZnO thin film. The influence of filming temperature during sputtering and the followed MST on the crystalline structure, transmittance, bonding environment, surface morphology, and electrical property of the ZnO thin films has been investigated. The formed compound on quartz glass could be identified as wurtzite ZnO. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results show that the crystalline quality improves with raising the filming temperature. In addition, K 2p XPS spectra hint that the outside surface of ZnO thin films contains a certain amount of K, after MST for ZnO thin films. Compared with that of the followed MST, atomic force microscope (AFM) results also show that the filming temperature significantly affects surface morphology. More importantly, the ZnO thin films obtain p-type characteristics after MST for ZnO n-type thin films, with excellent transmittance and increased mobility.

Lignocellulosic-biomass-derived transparent nanopaper is an emerging substrate or functional component for next-generation green optoelectronics. The fabrication of such transparent nanopaper typic...

Numerous oxygen elements are present on the oxidized coal surfaces, resulting in the difficulties for flotation. In this study, the enhancement of oxidized coal flotation using the impact flow cond...

The Al–Hf alloy was prepared by open aluminothermic reduction of HfO2 using CaF2 and NaF as the flux. The influence of the slag composition, the amount of aluminum, and the heat energizer was studied detailly to establish optimum conditions for the sufficient recovery of the alloy and the complete slag–alloy separation. The Al–Hf alloy with 40 wt% Hf was obtained by this method, and the maximum recovery was 70.7%. The microstructure of the alloy was observed by scanning electron microscope (SEM). Moreover, X-ray diffraction (XRD) analysis and energy-disperse spectrometry (EDS) were applied to characterize the formation of the phases. The results show that the alloy consists of Al and Al3Hf phases and the oxygen content is about 0.2 wt%.

Vertical-cavity surface-emitting lasers that can be controlled to emit hollow laser beam in certain LP21 mode are proposed and fabricated. A circular inverted surface relief with precisely designed diameter and thickness is introduced through theoretical simulation. The fabricated device shows a stable single LP21 mode operation with excellent robustness of mode and power to temperature. Preliminary analysis attribute the excellent performance of the device to the inverted surface relief, leading to hollow near-field spot distribution.

Rutile titania (TiO2) was successfully prepared via hydrolysis of TiCl4 in the presence of AlCl3. The powders were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) surface area analysis. In the present system, AlCl3 functions as a nucleating agent and induces the formation of rutile TiO2. The influences of HCl and isopropanol concentrations on the purity and morphology of the rutile TiO2 were investigated. The purity of the rutile TiO2 increased with increasing concentration of HCl. Evenly dispersed rutile TiO2 particles with a spherical morphology were obtained when the HCl and isopropanol concentrations were 0.5 and 1 mol·L−1, respectively. Furthermore, the prepared TiO2 powders were used in adsorption tests of the heavy metal pollutant Cr(VI). Rutile TiO2 sample S-9 demonstrated greater adsorption performance and a removal efficiency that was greater than 99.95% after 60 min of adsorption when the Cr(VI) concentration was 200 mg·L−1 The maximum adsorption capacity on rutile TiO2 was 28.9 mg·g−1. This work provides an easy path to prepare a high-performance rutile TiO2 adsorbent with potential applications in water pollution treatment.

Minimizing lattice thermal conductivity, κl, of thermoelectric materials is an effective strategy to enhance their figure-of-merit, zT. However, the amorphous limit of κl affects the ceiling of the attainable zT. Herein, we fabricate hierarchical structures by using an in situ microwave synthesis to break the amorphous limit of κl for achieving a high zT in (Sn0.985In0.015Te)1–x(AgCl)x alloys. Our results from detailed electron microscopy characterizations suggest that the as-sintered (Sn0.985In0.015Te)1–x(AgCl)x alloys contain a range of lattice imperfections, including microsized grains with dense grain boundaries, nanopores with sizes from several to hundreds of nanometers, and nanoscale precipitates, which result in strong phonon scatterings and in turn lead to a minimized κl of 0.245 W m–1 K–1. Moreover, the calculated band structures reveal the introduction of resonance level by In doping, which dramatically enhances the electrical transport properties to ensure a high power factor of 26.4 μW cm–1 K–2 at 823 K and a maximum zT of 0.86 (823 K) in hierarchically structured (Sn0.985In0.015Te)0.90(AgCl)0.10. This work provides a new approach to modulate the hierarchical structures for optimizing thermal and electronic transport properties.

A prototype of temperature-responsive protective fabric assembly with shape memory alloy (SMA) spring was developed. The effect of moisture on the thermal protective performance of fabric was investigated under radiant heat exposure and hot surface contact. The thermal liner of fabric system was pretreated with moisture amount of 25%, 50%, and 100%. Meanwhile, the thermal protection of fabric assembly with SMA springs in different positions between the fabric layers was explored. The results showed that moisture above 25% had a positive influence on thermal protective performance of both traditional and SMA fabric assembly under two hazardous environments. The effect of moisture in SMA fabric assembly was more remarkable than that in fabric without spring. And the SMA spring located between thermal liner and moisture barrier provided better thermal protective performance. The research findings will be beneficial for manufacturing high-performance temperature-responsive fabric.

The surface wettability of micron particles affects many engineering applications, such as forth flotation and dust removing. The settling velocities of glass beads with diameters in the range 15–100 μm and varying surface wettability were obtained using a high-speed dynamic system. The results showed that the surface wettability of the particle surface has a significant effect on the terminal settling velocity (VT) when the particle dimensionless diameter (d∗ = (∆g/v2)1/3d) is less than two. As the contact angles increase, the VT increases and the drag coefficient (CD) decreases. The classical Stokes model does not reflect this change; consequently, a modified Stokes model that considers surface wettability is proposed. Experimental results indicate that the average relative error of the proposed model is 3.10% for the modified settling velocity formula, and 3.06% for modified drag coefficient formula. Both modified formulas were validated using the experimental data of spherical aluminum oxide (Al2O3) particles.

Faced with the challenge of high energy ablation problems, especially for laser ablation, effective energy dissipation protective materials fabricate by efficient preparation method is a feasible solution. The Ni-graphite/SiO2 coatings with different Ni content were prepared by plasma spraying method with optimized plasma spraying parameters. All coatings are pure without oxidation and dense. Their ablation behaviors were investigated by high power continuous wave laser. The results indicate that the Ni-graphite/SiO2 coating with appropriate Ni content could realize the purpose of energy consumption by endothermal reaction of graphite/SiO2 and reflection improvement. High Ni content will block the occurrence of endothermal reaction of graphite/SiO2 and increase the heat diffusion to interior part of coating, which can make the ablation situation of coating more serious.

A dense discrete phase model combined with the kinetic theory of granular flows was used to study the bubbling characteristics and segregation of poly-dispersed particle mixtures in a thin fluidized bed. Our simulations showed that in using the hybrid Eulerian–Lagrangian method, the common use of one computational cell in the thickness direction of the thin bed does not predict wall friction correctly. Instead, a three-cell discretization of the thickness direction does predict the wall friction well but six cells were needed to prevent overprediction of the bed expansion. The change in specularity factor (SF) of the model not only affected the predictions of the velocity of particles, but also had a considerable impact on their flow pattern. A decrease in SF, which decreases wall friction, showed an over-prediction in the size of bubbles, particle velocities, and void fraction of the bed, and led to a shift in the circulation center toward the bottom of the bed. The segregation of the Geldart B particles was studied in the narrow range from 400 to 600 μm with a standard deviation less than 10% of the average diameter. Simulations showed that large particles accumulated close to the distributor at the bottom of the bed and the center of the bed, but small particles moved towards the wall and top surface. The decrease in the mean particle size and spread in shape of the distribution improves mixing by up to 30% at a superficial gas velocity of around 2.5 times the minimum fluidization velocity. Log-normal mixtures with a small proportion of large particles had the most uniform distribution with a thin layer of jetsam forming at the bottom of the bed. Finally, experimental verification of the segregation and mixing of polydisperse particles with narrow size distribution is suggested.

The objective of this article is to investigate the effect of contact material on the formation and transition of high-current anode spots and anode plumes. A series of experiments are carried out in a demountable vacuum chamber at three current levels of 3, 4, and 6.5 kA. Plate contacts made of CuCr30 and CuCr40 with a diameter of 10 mm are adopted. Arc images are captured by a high-speed camera and synchronized with measurements of the arc current and voltage. The experimental results show that the three typical anode discharge modes, namely footpoint, anode spot type 1, and anode spot type 2, are formed at a smaller gap distance as the experimental current increases, and this tendency is independent of the contact material. The arc voltage is higher and the anode spot appears earlier and lasts longer under the CuCr40 contact than under the CuCr30 contact. As a result, the footpoint is formed at a smaller gap distance, whereas anode spot type 2 is formed at a larger gap distance. As a special anode discharge mode, an anode plume usually occurs between anode spot type 2 and arc current zero in various shapes at different locations on the anode surface. The anode plume of the CuCr40 contact appears at a larger gap distance and the corresponding threshold current and accumulated arc energy are also larger. Due to a stronger anode activity, the anode plume lasts a longer time under the CuCr40 contact than under the CuCr30 contact.

Multi-arc ion plating was used to deposit TiAlN/CrN multilayer coatings with different bilayer thicknesses on Type 316L stainless steel. The impacts of the bilayer thickness on the electrochemical performance of the TiAlN/CrN multilayer coatings were explored in a neutral saline (3.5% NaCl) solution. The fracture cross-sectional morphology of the as-deposited coatings were investigated by scanning electron microscope. The crystal structure and preferred orientation were analyzed by x-ray diffraction. The interface characteristic was detected by transmission electron microscopy. The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used for as-deposited coatings. Corroded surface morphology and EIS of the 15-day immersion coatings and substrate were examined to analyze the anticorrosion performance. EIS showed an increase of polarization resistance (Rp) and a decrease in constant-phase element (CPE) for multilayer coatings with a decrease in bilayer thickness. After 15 days of immersion, the EIS plot showed that the C3 coating (with 20 bilayers) had the lowest electrical double-layer capacitance (CPEdl) and highest charge transfer resistance (Rct) in all samples. The relative decay of the Rp of the C3 coating was the smallest compared with the as-deposited coatings, which shows a satisfactory corrosion resistance. The electrochemical tests and immersion corrosion morphology showed that the existence of a large number of interfaces between individual layers in a multilayer structure inhibits the pitting propagation significantly and enhances the corrosion resistance.

In this paper, we present a detailed investigation of three types of tapered distributed feedback (DFB) quantum cascade lasers (QCLs) emitting at $7.2~\mu \text{m}$ . The sampling gratings with different sampling duty cycles were fabricated by holographic lithography combined with the conventional optical photolithography. High output power of more than 550mW with excellent beam quality was achieved in continuous-wave operation at 293K for a 2.5-mm-long DFB-QCL with sampling duty cycles of 0.25 and 0.5 in the tapered region and uniform region, respectively. Stable single-mode emission with a side-mode suppression ratio above 25dB was obtained in the temperature range of 283-318K. The demonstrated tapered DFB QCL structure with asymmetric coupling coefficient can effectively achieve high performance with low fabrication cost, which is beneficial for many applications.

The effects of parboiling processing (121 °C for 10, 15, and 20 min, 0.1 MPa) on thermal properties, color value, morphological properties, and crystallinity of highland barley were studied. During 20 min parboiling processing, the color values Chroma B*, b* values increased, and L* values decreased; the crystallinity of parboiled barley illustrated A, B, and V-style polymorphs; the heat enthalpy (ΔH) and onset, peak, conclusion temperature of gelatinization, and range of gelatinization (To, Tp, Tc, and Tc-To) was decreased; the internal structure of highland barley was destroyed. Meanwhile, the crystallinity was observed to be significantly correlated to color values and thermal properties during different degrees of processing.

The influence of small amounts of cerium on the solidification phenomena of S31254 high-Mo austenitic stainless steel was investigated by in situ observations and theoretical calculations. In situ observations indicate that cerium addition in molten steel can accelerate austenitic nucleation but inhibit primary austenite grain growth. The initial nucleation temperature occur 32.3 °C in advance and the nucleation site density increases to 176/mm after 2 seconds in S31254-Ce compared to S31254. The modified Ce-containing inclusions in S31254-Ce improve the ability for austenite heterogeneous nucleation, which would significantly reduce the energy barrier of nucleation. The nucleation mechanism obtained from Johnson–Mehl–Avrami–Kologoromov (JMAK) theory is changed from site saturation nucleation to site saturation plus Avrami nucleation after cerium addition. Furthermore, cerium addition also prolongs the whole solidification temperature range from 28 °C to 43.9 °C and limits the growth velocity of a single austenite grain from approximately 20 to 2 μm/s. The ratio of the solid phase decreases from 60 to 8.2 pct, but the grain density increases from 68.8 to 280/mm2, with the solidification time extended to 8 seconds after cerium addition. Thus, the main solidification behavior in the early solidification stage of S31254-Ce is nucleation instead of primary grain growth. The low growth velocity for austenite grains and significant high nucleation site density exhibit a low rate constant k during the solidification process. Moreover, cerium addition could significantly refine the solidified structure, and the grain density of the final solidified structure in S31254-Ce is 366.6/mm2.

GeTe-based materials usually possess brilliant thermoelectric performance through band degeneracy and optimized carrier concentration. In this study, Ti doping is effective for the realization of b...

The laser-matter interaction contains complex thermophysical and thermochemical responses. The variation of energy and composition happen in thermophysical and thermochemical process will totally change the interaction behaviors. In order to obtain an accurate mechanism and promote the understanding of laser-matter interaction, all thermophysical and thermochemical responses, especially the thermochemical part, should be considered and investigated. In this study, a coupled heat-matter diffusion model based on thermodynamic chemical equilibrium finite-element method and thermochemical ablation theory was established. The materials with complex reaction enthalpy change in high temperature environment were chosen to validate the model. The results show that this model is accurate, as the maximum error of back-surface temperature response is just 4.0% between experimental and calculation values. The detailed variations of composition, temperature and optical reflection were obtained and analyzed, which is in good agreement with the experiment. This coupled heat-matter diffusion model including all thermophysical and thermochemical response has the great potential in nearly all laser-matter interaction involved application.